Chair-iron.



H. W. BOLENS.

CHAIR IRON. APPLICATION FILED rzmza. 191s.

1,32,21. I Patented June 12, 1917.

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HARRY W. BOLENS, 03? PORT WASHINGTON, WISCONSIN.

CHAIBFIRON' Specification of Letters Patent.

Patented June 12, 1917.

Application filed February 23, 1915. Serial No. 9,928.

To all whom it may concern.

Be it known that T, HARRY W. BoLENs, a citizen of the United States, and resident of Port l Vashington, in the county of Ozaulree and State of Wisconsin, have invented certain new and useful Improvements in Chair-Irons; and I do hereby declare that the following is a full, clear, and exact description thereof.

My invention refers to spring-controlled tiltable chair irons, especially of the compression type and the object of said invention is to provide a simple, durable and effective means for regulating the spring resistance relative to heavy and light load conditions without appreciable variation in the tension of the spring, whereby the life of the same is increased and the tilt of the spider in opposition to said spring resistance produces a soft cushion effect under maximum and minimum load conditions in contradistinction to the abrupt stiff spring action usually manifest in chair irons of the above character wherein the spring coils are over-compressed in order to oppose heavy load strain, such deadening compression re-' sulting in crystallization and breakage. The desirable result through my novel arrangement is attained by a construction and arrangement permitting shift of the spring loading point relative to the axis of oscillation of the spider, whereby said loading point is moved toward or away from the point of oscillation of the spider for maxi mum and minimum load conditions respectively. Hence the load point of the spider which compresses the spring exerts greater or less leverage relative to the power of load whereby said spring may be compressed'with equal ease by light or heavy persons.

WVith the above objects in view the invention consists in what is herein shown, described and claimed.

In the drawings Figure 1 represents a sectional elevation of a chain iron embodying the features of my invention, the section being indicated by line 11 of Fig. 2;

Fig. 2, a sectional plan view of the same, the section being indicated by line 22 of Fig. 1, and

Fig. 3, a detailed sectional view showing a spring-seating block in elevation, the section being indicated by line 3-3 of Fig. 1.

Referring by characters to the drawings,

1 represents a spindle having an apertured head 2 secured thereto, which head carries the ordinary pivot bolt 3 that extends therethrough and has mounted thereon ears 1 of a saddle 5. The bridge-piece 5 of the saddle is centrally depressed for the reception of a spider-arm 6 and a companion spider-arm 6 is secured to the upper face of the bridge to extend crosswise of the first mentioned fore and aft spiderarm 6. The rear portion of the saddle has fitted thereto a spring seating block 7 provided with a central aperture 7 and companion nibs 7 for the reception of the forward ends of a pair of coiled springs 8. The rear ends of these springs are fitted over nibs 9 of a spring-retaining strap 9. The strap 9 is centrally apertured for the reception of the rear free end of a spring-confining rod 10, which end is threaded and adapted to receive an adjusting nut 10 that impinges against the outer face of the strap. The inner or front end of the spring-confining rod 10 carries a head sleeve having wedgeshaped feet 11 extending therefrom, which feet engage transverse notches 11 that are formed adjacent to the slotted end of a lever arm 12, it being understood that the rod 10 projects through and has vertical play in the slot 7 of the spider-carried spring-seating block 7.

As best shown in Fig. 2, oscillatory move ment of the spider is limited in either direction through engagement of its ears 4 with front and rear offset lugs 4:, l", respectively, which lugs project from the exterior walls of the spindle-head. The slotted end of the lever-arm 12 is, as shown, positioned above the pivot-bolt 3 and normally the point of anchorage between the arm and spring-confining rod 10 is rearwardly of an imaginary vertical line inter secting the bolt 3 which constitutes the axis of oscillation of the spider. The lever arm is pivotally' mounted upon the pivot-bolt 3 and in this exemplification of my invention said lever arm is in the form of a bell-crank having an adjusting arm 12 which projects forwardly from the arm 12, which adjusting arm carries a tension bolt 13 that extends downwardly and through a slotted recess 2 that is formed in an extension of the spindle head. The tension bolt is in threaded engagement with an adjusting nut 13 which impinges against the lower face of the head extension.

From the foregoing description it will be observed that, in this exemplification of my invention, the springs are interposed between the strap 9 and spider block 7 and the said strap in connection with the rod 10 constitutes a shackle connection for the springs, which shackle connection is adjustably secured at its inner end to the spindle head by the bell crank lever comprising the arms 12, 12, that is pivotally mounted within the head, as previously stated, being extended through'said head aperture, whereby access is conveniently had for pivoting the arm to the pivot-bolt. The springs are put under a normal compression by adjusting the nut 10 upon the rod 10 at the free or floating end of the shackle connection and in order to compensate for maximum or minimum load strain upon the coiled springs, adjustment of the bell-crank lever mechanism is effected.

By referring to F ig. 1 of the drawings, it will be observed, for example, that the position of the outer end of the lever arm 12, with relation to a vertical line intersecting its axis of movement, is rearward and it follows that the point of connection between the rod 10 and said arm are in a like position. Should it be desiredto render the spring mechanism more sensitive, the nut 13 is manipulated to permit the lever arm 12 to swing farther rearward and in describing an arc of a circle with relation to its axis, it will be observed that the point of connection between said arm and the springconfining rod will drop downwardly or closer to the axis of oscillation of the spider. Hence the point of leverage between the rod and pivot-bolt 13 being relatively short, it is manifest that a light load will be sufficient to compress the spring due to this change of leverage and it should further be under stood that, in effecting this change of position, there is only a slight release upon the 1 Copies of this patent may be obtained for through the point of oscillation of said lever-arm. Thus the distance between the anchorage point of the spring shackle mechanism and the pivot bolt 3will be materially increased while the tension of the springs is only increased to a slight degree. Hence, due to the long leverage in connection with the spring mechanism, the heavy load upon the chair spider will act to compress the springs in a similar manner to that described previously and said compression for light or heavy load will thereby be approximately equal with but slight variation in the initial load compression placed upon the same. 1

While I have illustrated one exemplification of my invention wherein for convenience the bell-crank lever arm for adjusting the shackle mechanism as being mounted directly upon the pivot-bolt 3, it is obvious that the same result may be attained by employing an individual fulcrum point, the essential feature being the arrangement whereby the point of connection between the spring-supporting shackle and head is varied with relation to the axis of oscillation of the spider.

I claim:

A chair iron comprising a spindle head provided with an aperture, a pivot shaft carried by the head adjacent and below said aperture, a spider, depending arms on the spider journaled on the shaft, a spring seating block carried by the spider, an angle lever including a short arm extended upwardly between the spider and spindle head and a long arm extending away from the spring seating block and an extension at its angle projecting through the aperture of the head and pivoted on the bolt, a spring ex tending outwardly from the seating block, a rod connected with the outer end of the spring and pivotally connected with the short arm of the lever and means for adjustably holding the long arm of the lever with respect to the spindle head.

In testimony that I claim the foregoing I have hereunto set my hand at Milwaukee in the county of Milwaukee and State of VVisconsin in the presence of two witnesses.

7 HARRY W. BOLENS. Witnesses: i

I Geo. W. YOUNG, M. E. DOWNEY.

five cents each, by addressing the Commissioner of Patents, Washington, D. G. a 

